I am very disappointed with the children

The children are playing on the computer for 6 hours at a stretch like there is no tomorrow.
On a typical day, the girl will begin playing on the computer while the boy go to school for classes and when the boy comes home, he will chase away the girl and starts playing on the computer for a continuous stretch of more than 6 hours.
After dinner, the girl will continue playing on the computer as though it is her time to play because the boy had his time already.

This happen when they are on school holidays and it is understood that Diana allow them to use the computer.

After all the talks about their examinations results, it is a total waste of time because they just simply don't care. They are still not aware of the implications of their actions and just wanted to play. They have not understand why it is so important to have good results. To put it simply, their brains is not open yet. Sigh.............